Electric furnace.



No. 643,254. Patented Feb. I3, |900.

A. J. PETERSSUN.

ELECTRIC FURNACE.

(Application led Apr. 5, 1898.) v (No Model.) 3 Shets-Shet l.

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10.643,254. Patented Fen. I3, |900. A. J. PETEnssoN.

ELECTRIC FURNAGE.

(Application med Apr. 5, 189s.)

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Patented Feb. 3,1900.

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WRX/Mom z UNITED STATESv PATENT Onncn.

ALBERT JOHAN PETERSSON, OF NOTRE DAME DE BRIANOON, FRANCE, ASSIGNOR TO THE SOCIETE DES OARBURES METALLIQUES, OF PARIS,

FRANCE.

ELECTRIC FU RNACE.

SPECIFICATION forming part of Letters Patent N o. 643,254, dated February 13, 1900.

Application filed Apil 5, 1898. Serial No. 676,530. (No model.)

To all wtmit it may con/cern:

Be it known that I, ALBERT JOHAN PETERS- SON, a subject of the King of Sweden and Norway, residing at Notre Dame de Briancon, in the Department of Savoie, France, have invented a new and useful Electric Furnace, (for which I obtained French Letters Patent No. 270,513, dated September 16, 1897, and German Letters Patent, dated November 22, 1897,) which invention is fully set forth in the following specification.

The present invention has for its object a new electric furnace especially suitable for the manufacture of calcium carbid. It is known that one of the great inconveniences of furnaces of this sort is the waste of the electrodes, especially of the upper electrode, for the lower electrode, which is in the bath of liquid carbid, wears away at a much slower rate.

The furnace vthe object of the present invention is characterized particularly by a special arrangement of the two electrodes, which are arranged at the base of the oven, so as to be entirely covered by the bath while the reduction of the materials is taking place, and which consequently are very slowly expended. The electrodes consist of two horizontal plates of iron covered with a layer of carbon. In place of plates bars of iron may be employed, arranged parallel, suitably connected together, and also covered with a layer of electrode carbon. The electrodes thus constituted are arranged in the bottom of the furnace, so as to be entirely covered by the bath of carbid, so that the materials to be reduced are not traversed by the current, but are heated by contact vwith the bath. The bath itself is heated by the resistance which it opposes to the passage of a current of great intensity between the electrodes.

The furnace is continuous in its action, and the height of the bath is kept constant by means of one or more draw-off holes placed at a suitable height at the upper part of the bath. The operation maybe started by placing in the lower part of the furnace between the two electrodes a layer of carbid in small pieces, which connects the electrodes and melts on the passage of the current. A core of carbon or other conductor may also be em ployed to connect the two electrodes. This core disappears gradually during the operation.

The walls of the furnace, which are in contact with the carbid, should be formed of nonconducting material capable of enduring the temperature of the fused carbid.

The furnace which is the object of the present invention may be formed in two parts, the one fixed, which contains the material to be melted, and the other movable and which will be a sort of carriage carrying the bath and the electrodes. Then in the fixed part of the furnace a number of fines are formed. They are suitably arranged, and in them the gases disengaged by the reaction pass. Air is caused to enter these flues by openings formed with this object, and the air effects the combustion ofthe gases in the iues. The gases thus serve to heat the mixture to be melted as it descends in the furnace, so facilitating the fusion as the material enters the bath. By means of these iiues the combustion of the gas in the midst of the mass to be melted is prevented, for this would be prej udicial to the proper conduct of the operation, for a part of the carbon required in the mixture would be consumed, and the proportion of this would be in consequence altered.

The annexed drawings show the arrangement of the furnace constructed in accordance with the present invention.

Figure 1 is a longitudinal section on the center line of the furnace. Fig. 2 is a vertical section on the line 2 2 in Fig. l. Fig. 3 is a section upon the line 3 3 in Fig. 1. Fig. t is a horizontal section on the line 4c a in Fig. 1.

The arrows indicate the direction taken by the gaseous products in the reaction. The arrows marked 1 indicate the entrance of air into the furnace.

A is the xed part of the furnace, provided with flues a, in which the combustion of the gaseous products of the reaction takes place.

a are the apertures which lead air into the flues a. The ignited gases are led by the orifices c? into the lateral channels a3, in which they circulate around the furnace and then escape into an outlet-chimney. (Not shown in the drawings.)

It may be remarked that the outlet chim- IOO ney or stack of the furnace is in form slightly conical, so as to facilitate the descent ot' the material to be melted.

B is the movable part of the furnace, in which are the bath of carbid and the two electrodes c c". The electrodes c c are placed horizontally, or substantially so. The walls l? are formed of non-conducting material which Will stand the temperature at which the carbid fuses. Under the electrodes vacant spaces b' are formed for the circulation of air. h2 are channels formed beneath the bath for the circulation of air.

D is an outlet-hole.

The part B or oven is arranged below the part A and is provided with a iat hearth adapted to receive the red uced material. The electrodes c care arranged in the hearth and have their upper surface level with the hearth.

It is hardly necessary to state that the details may be varied as may be required. For example, it is not necessary that the bottom of the furnace should be movable. It may in some cases be xed. In place of the ilues simple partitions may be provided to divide the mass.

l. In an electric oven, a chamber for the reception of the material to be reduced, an oven arranged below said chamber and having a flat hearth adapted to receive the reduced material, and two electrodes arranged in and having their upper surfaces level with the hearth of said oven, the upper lat surfaces of said electrodes adapted to be covered by and in Contact with the reduced material and out of contact with the unreduced material, all arranged so that the reduced material on and between the electrodes is heated by the resistance it opposes to the passage of the current between the electrodes, the-circuit of which is completed by said reduced material and the unreduced material is heated and reduced by contact solely with the heated reduced material, substantially as and for the purposes described.

2. In an electric oven,two superposed chambers of which the lowermost is movable and the uppermost fixed, said fixed chamber adapted to receive and feed the material to be reduced and said movable chamber having a hearth adapted to receive the reduced material, in combination with two electrodes of relatively large area and arranged in substantially a fiat or horizontal position in said hearth, the upper surfaces of the electrodes being level with said hearth, substantially as and for the purposes described.

In an electric furnace, two chambers arranged as described, the upper chamber being adapted to receive and feed the material to be reduced and the lower chamber having a hearth adapted to receive the reduced material, two electrodes of relatively large area and arranged horizontally in the hearth of the lower chamber, lues traversing the upper chamber and adapted to receive and burn the gases arising from the other chamber, said flues leading vertically from the lower portion of the upper chamber and opening directly into the lower chamber, and auxiliary air-dues adapted to conduct air into the gas-ilues at or near their lower end, substantially as and for the purposes described.

In testimony whereof I have signed this specication in the presence of two subscribing witnesses.

ALBERT JOHAN PETERSSON.

Vitnesses:

T. BOUTELLE, GURIN. 

